<?xml version="1.0" encoding="utf-8"?>
 <element xmlns="http://relaxng.org/ns/structure/1.0" 
  name="library" 
  ns="http://eric.van-der-vlist.com/ns/library">
  <oneOrMore>
   <element name="book">
    <attribute name="id"/>
    <attribute name="available"/>
    <element name="isbn">
     <text/>
    </element>
    <element name="title">
     <attribute name="xml:lang"/>
     <text/>
    </element>
    <zeroOrMore>
     <element name="author" ns="http://eric.van-der-vlist.com/ns/person">
      <attribute name="id"/>
      <element name="name">
       <text/>
      </element>
      <element name="born">
       <text/>
      </element>
      <optional>
       <element name="dead">
        <text/>
       </element>
      </optional>
     </element>
    </zeroOrMore>
    <zeroOrMore>
     <element name="character">
      <attribute name="id"/>
      <element name="name" ns="http://eric.van-der-vlist.com/ns/person">
       <text/>
      </element>
      <element name="born" ns="http://eric.van-der-vlist.com/ns/person">
       <text/>
      </element>
      <element name="qualification">
       <text/>
      </element>
     </element>
    </zeroOrMore>
   </element>
  </oneOrMore>
 </element>
